1. Field of the Invention
The present invention generally relates to a routing structure, in particular, to a routing structure and a routing method of a re-distribution layer (RDL).
2. Description of Related Art
In modern time, the multimedia application market is expanding quickly. The packaging technique of integrated circuits must be developed to meet the development of such electronic devices. In order to achieve the above requirements, it is necessary to strengthen the features of high-speed processing, multifunction, integration, small scale and light-weight, low price, etc. of the electronic devices. Accordingly, the development of the packaging technique of integrated circuits also tends towards minimization and high density of the size.
The packaging density of an integrated circuit refers to the number of pins in a unit area. For a high-density integrated circuit package, reduction of the wire length between the integrated circuit and the package substrate benefits the speed of signal transmissions. Therefore, the flip-chip package technique using routes for transmitting signals has become the mainstream technique in the high-density package.
For example, bumps of a wiring bonding chip are usually arranged in a peripheral type, and are electrically connected to wire bumps on a package substrate through wires. Meanwhile bumps on a flip chip are usually arranged in an array type, and are electrically connected to route bumps on the package substrate through routes. The flip-chip packaging technique has gradually become the mainstream technique, and more products are packaged by using the flip chip technique. However, altering the current design of a product to catch up with the change of package technique may not be cost effective.
Therefore, a pad re-distribution technique is developed. A re-distribution layer (RDL) is disposed on the top metal layer of the former wire bonding chip, the bumps originally arranged in the peripheral type of the wire bonding chip are re-distributed to become an array type of the flip chip bumps, for disposing the routes required by the flip-chip package.
However, the routing structure of the RDL of the conventional art focuses more on how to provide the power source to a core circuit in the chip instead of reducing the noises generated in the routing structure.